Radiological impact of phosphogypsum surface application in a no-till system in Southern Brazil

Abstract

The objective of this work was to determine the impact of phosphogypsum application on ²²⁶Ra and ²²⁸Ra activities in the soil and on their accumulation in soybean grains. A field experiment was carried out in Paraná state, Brazil, on a loamy Typic Hapludox, under no-till system, with increasing phosphogypsum rates: 4, 8, and 12 Mg ha^-1. Gamma-ray spectrometry was carried out using HPGe detectors with 45 and 10% relative efficiencies, for soybean grains and soil, respectively. No increment of ²²⁶Ra and ²²⁸Ra activities was observed due to the increase in phosphogypsum rates in the soil, and a small reduction was noticed in the grains. Average values found for ²²⁶Ra and ²²⁸Ra activities were 37 and 57 Bq kg^-1 in the soil and 1.44 and 3.19 Bq kg^-1 in soybean grains. The application of phosphogypsum for no-till soybean production is a safe practice regarding the risks of radiation damage to human health.